Class ReloadableResourceBundleMessageSource

All Implemented Interfaces:
Aware, HierarchicalMessageSource, MessageSource, ResourceLoaderAware

public class ReloadableResourceBundleMessageSource extends AbstractResourceBasedMessageSource implements ResourceLoaderAware
Spring-specific MessageSource implementation that accesses resource bundles using specified basenames, participating in the Spring ApplicationContext's resource loading.

In contrast to the JDK-based ResourceBundleMessageSource, this class uses Properties instances as its custom data structure for messages, loading them via a PropertiesPersister strategy from Spring Resource handles. This strategy is not only capable of reloading files based on timestamp changes, but also of loading properties files with a specific character encoding. It will detect XML property files as well.

Note that the basenames set as "basenames" property are treated in a slightly different fashion than the "basenames" property of ResourceBundleMessageSource. It follows the basic ResourceBundle rule of not specifying file extension or language codes, but can refer to any Spring resource location (instead of being restricted to classpath resources). With a "classpath:" prefix, resources can still be loaded from the classpath, but "cacheSeconds" values other than "-1" (caching forever) might not work reliably in this case.

For a typical web application, message files could be placed in WEB-INF: e.g. a "WEB-INF/messages" basename would find a "WEB-INF/", "WEB-INF/" etc arrangement as well as "WEB-INF/messages.xml", "WEB-INF/messages_en.xml" etc. Note that message definitions in a previous resource bundle will override ones in a later bundle, due to sequential lookup.

This MessageSource can easily be used outside an ApplicationContext: it will use a DefaultResourceLoader as default, simply getting overridden with the ApplicationContext's resource loader if running in a context. It does not have any other specific dependencies.

Thanks to Thomas Achleitner for providing the initial implementation of this message source!

Juergen Hoeller, Sebastien Deleuze
See Also: